This invention relates in general to universal joints and in particular to an apparatus for facilitating the installation and removal of a bearing cup on a trunnion of a cross connected to a yoke of a universal joint.
Universal joints are well known devices that provide a driving connection between two members adapted to rotate about non-aligned axes of rotation. A typical universal joint includes a cross having a central body portion with four cylindrical trunnions extending outwardly therefrom. The trunnions are oriented in a single plane and extend at right angles relative to one another. A hollow cylindrical bearing cup is mounted on the end of each of the trunnions. Needle bearings or similar means are provided between the outer cylindrical surfaces of the trunnions and the inner cylindrical surfaces of the bearing cups to permit relative rotational movement therebetween. The bearing cups mounted on a first opposed pair of the trunnions are connected to a first yoke secured to an end of a first member, while the bearing cups mounted on a second opposed pair of the trunnions are connected to a second yoke secured to an end of a second member.
One type of yoke that is commonly used in connection with universal joints is a full round end yoke. A typical full round end yoke includes a body portion having a pair of opposed arms extending therefrom. The opposed arms extend outwardly from the body portion in a cantilevered manner. A pair of aligned openings are formed through the opposed arms of the full round end yoke. To assemble a universal joint with a full round end yoke, one of the opposed pairs of trunnions is initially positioned within the aligned openings formed through the opposed arms of the full round end yoke. The bearing cups containing the needle bearings are then disposed about the ends of the opposed pair of trunnions by moving the bearing cups inwardly through the opposed openings formed through the opposed arms of the end yoke and onto the associated trunnions. Snap rings or other retainers may then be applied to retain the bearing cups on the associated trunnions.
It is usually desirable that the bearing cups engage the inner surfaces of the associated openings in a press fit relationship. Thus, the amount of force required to move the bearing cups through the openings formed through the opposed arms of the full round end yoke during the installation process is relatively large. To accomplish this, it is known to use a mechanical press to move the bearing cups through the openings formed through the opposed arms of the full round end yoke during the installation process. Typically, one of the opposed arms of the full round end yoke is initially positioned against a fixed reaction surface of the mechanical press so as to provide support. Next, the bearing cup is positioned adjacent to the opening formed through the other of the opposed arms. The mechanical press is then actuated to drive a push rod against the bearing cup, thereby moving the bearing cup through the opening in the opposed arm. The other bearing cup can be installed in a similar manner. The same mechanical press can be used in a similar manner to remove the bearing cups from the trunnions, such as may be desirable when servicing the universal joint.
As mentioned above, the bearing cups usually engage the inner surfaces of the associated openings in a press fit relationship, requiring the exertion of a relatively large amount of force to move the bearing cups through the openings. In conventional yokes that are formed from a relatively strong material, such as steel, the exertion of these forces can be absorbed by the yoke without causing any damage thereto. In newer yokes that are formed from lighter weight materials, such as aluminum, the exertion of these forces can cause flexing of the opposed arms of the yoke during the installation of the bearing cups. Such flexing is undesirable because it can introduce stresses in the opposed arms of the yoke and, in extreme instances permanently deflect such arms. Thus, it would be desirable to provide an apparatus for facilitating the installation and removal of a bearing cup on a trunnion of a cross connected to a yoke of a universal joint that prevents such undesirable deflections.